1. Field of the Invention
This invention relates to brain infusion techniques, and more particularly relates to such techniques for treating neurodegenerative disorders.
2. Description of Related Art
PCT Publication Number WO 93/06116, filed Sep. 17, 1992 (the "'116 Publication"), suggests the use of GDNF for preventing and treating nerve damage and nerve related diseases, such as Parkinson's disease, by implanting into the brains of patients cells that secrete GDNF. Certain membrane devices are described for such implantation.
PCT Publication Number WO 93/08828, filed Nov. 6, 1992 (the "'828 Publication"), suggests the intravenous application of certain nerve growth factors for the treatment of neuronal damage associated with ischemia, hypoxia or neurodegeneration, and teaches that intracerebroventricular administration is to be avoided because it is "difficult to implement and is associated with [a] relatively high degree of risk compared to intravenous administration." (P. 5, lines 15-17.)
PCT Publication Number WO 90/07341, filed Jan. 5, 1990 (the "'341 Publication"), states that nerve growth factor (NGF) has been demonstrated to be a neurotropic factor for the forebrain cholinergic nerve cells that die during Alzheimer's disease and with increasing age. The '341 Publication also states that experiments in animals demonstrate that NGF prevents the death of forebrain cholinergic nerve cells after traumatic injury and that NGF can reverse cognitive losses that occur with aging.
European Patent Application EP 0450386 A2, filed Mar. 18, 1991 (the "386 A2 Publication"), suggests the use of Brain Derived neurotrophic Factor (BDNF) from recombinantly derived biologically active forms for treatment of Alzheimer's disease. BDNF promotes the survival of motor neurons in several species (Henderson, C. E., et al., 1993, Nature 363, 277), and also promotes the survival of cholinergic neurons of the basal forebrain following frimbrial transections (Knusel, B., et al., 1992, J. Neuroscience 12, 4391-4402).
None of the foregoing PCT Publications teaches an adequate delivery system for the administration of any nerve growth factor, or prescribes brain sites for effective administration of nerve growth factors. In addition, they do not suggest how the dosage of nerve growth factor can be effectively regulated during infusion. The present invention is directed to these difficulties which the prior art fails to address.